Influência da laserterapia de baixa potência na regeneração do músculo esquelético e no remodelamento da matriz extracelular após lesão aguda

Abstract

The muscle injuries represent a major clinical found in rehabilitation centers. Low-level laser therapy (LLLT) has demonstrated positive effects in modulating the inflammatory response, muscle tissue repair and the prevention of fibrosis. The aim this study was to evaluate the effects of low-level laser therapy (LLLT) on the repair of skeletal muscle in rats following acute injury through an analysis of morphological aspects, collagen fibers and the gelatinolytic activity of matrix metalloproteinase 2 (MMP-2) following injury. Wistar rats were divided into five groups: 1) control group; 2) sham group; 3) LLLT group; 4) non-treated injury group; and 5) injury + LLLT group. The acute injury was induced in tibialis anterior (TA) muscle by the contact with a cooled metal probe (3 mm in diameter) during 10 seconds, twice, in the same muscle area. LLLT was performed daily using an Aluminum Gallium Arsenide laser (780nm, output power of 40 mW, beam area of 0.04 cm2 and total energy of 3.2J). The muscles were analyzed at one, three and seven days. The results showed that LLLT induced a reduction in inflammatory infiltrate and myonecrosis after one day, an increase in the number of blood vessels after three and seven days as well as an increase in the number of immature muscle fibers and MMP-2 gelatinase activity after seven days. In conclusion LLLT has a positive effect on the inflammatory process, MMP2 activity and collagen organization and distribution in the repair process of rat skeletal.